1. Field of the Invention
This invention relates to improvements in an electronic tone used for the chime of a timepiece or the like. More particularly, the invention relates to an electronic sound generating circuit providing a sound which is closer to that of an actual mechanical tolling bell.
2. Prior Art
Various improvements have been made in the electronic tone used in the chime or melody of timepieces in order to make the electronic tone resembling a tone of an actual mechanical bell toll. For example, one improvement is an envelope effect, wherein the volume of an electronic tone is gradually attenuated with the passage of time.
However, even with these conventional improvements, the generated electronic tone lacks quality and depth of an actual mechanical bell toll.
There are two reasons for this. One is that the conventional artificial electronic tone includes only a single frequency component, whereas an actual mechanical bell toll includes a mixture of several frequency components. The other is that the volume of an actual mechanical bell toll does not merely attenuate with time but the volume undergoes slight changes while attenuating.
A sound produced by mixing several frequencies and by varying volume in small increments cannot be obtained with the frequency or volume varying method conceived of heretofore in the prior art. There is need of a novel method for producing such a sound.